As a related art, in the 3rd generation partnership project (3GPP), the high speed uplink packet access (HSUPA) system is standardized. In the HSUPA, maximum power reduction (MPR) to reduce the maximum transmission power is carried out. The MPR is carried out by reducing the maximum transmission power according to a reduction allowable value calculated on the basis of a value that is called cubic metric (CM) and is obtained from a transmission waveform for example (refer to e.g. “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; User Equipment (UE) radio transmission and reception (FDD) (Release 11),” 3GPP TS 25.101 V11.9.2, April 2014).
Furthermore, in the HSUPA, there is a method in which the CM value is calculated by using a baseband signal to be transmitted (refer to e.g. International Publication Pamphlet No. WO 2007/132916 (hereinafter, Patent Document 1)). Moreover, in single cell (SC)-HSUPA, there is a method in which, for calculate of the CM value, the time average of an exponential of the amplitude of a transmission signal is calculated by performing a product-sum operation of a transmission-power-dependent term including a modulation parameter that depends on the transmission power of the transmission signal and a time average term including only a modulation parameter that does not depend on the transmission power of the transmission signal (refer to e.g. International Publication Pamphlet No. WO 2010/109548 (hereinafter, Patent Document 2)).
Furthermore, in the 3GPP, the dual cell (DC)-HSUPA system, in which the respective signals generated by two carriers are simultaneously transmitted, is also standardized.